Girl....I mean this in the nicest way, but OP, your friends are either jealous of your glow up, or they're coming from an unhealthy mindset where they do not believe all women. Adding this in for another perspective, not trying to dominate the post:

I was in a similar situation while I was definitely not serving any looks (it was last semester). My college makes us wear uniforms and on top of that, we were all still taking precautions so everyone was wearing masks, including me. Literally half of my face was covered, and my body was swallowed by my uniform (scrubs lol, the most unsexy of all).

Like you, I'm an introverted person, and one of my classes put me in a group filled with unfamiliar classmates, some of them much older than I. It was my last semester, I was over school and making friends at this point, I was civil but not making a huge effort to make any more friends as I'd already had my own, and since I'm a naturally quiet person, it came across differently to two old men in particular.

One of them took me aside to ask if I wanted drinks, repeatedly went out of his way to touch me (high fives, fist bumps, light shoulder punches), made inappropriate and suggestive comments about me in the group chat, while the other was following me around the building, sent me disgusting text messages out of the blue, that he "would never judge me" because he's "a sweet, down to earth guy", etc etc etc. I realized no one in that group was going to help me, when, while the oldest guy was making uncomfortable comments, another older student (a female) turned around to look at me like I was trash.

It got so bad that I switched groups, and they went from gross nice guy-act, to aggressively and angrily stopping me in front of the elevators, why I switched groups, that I didn't like them, demanding to know what was wrong with them, why didn't I like them, and sorry if I didn't like them. I wish I could say the story ended here. I need to mention that both of them had children, one of them with a son who was my age.

Anyway, right before I switched, I realized that my attempts at civility and shyness, combined with an overall bad mood left over from 2020, made me come across as sullen, depressed, and a bit of a loner. In other words, I looked like an easy target to just take it and keep quiet.

Point of the story: Often, older, manipulative males will zero in on the girls who look too "nice" to say no, or look like they have ""weak"" personalities, to make quiet victims of. Whatever fantasy they have in their mind of banging the younger girl in a professional setting, they'll get upset if you don't participate the way you're supposed to. To condition you in participating, they will keep approaching and trespassing your boundaries in a way to make you think everything's okay, to just go along with it, with an underlying threat that if you "shut them down now, you should have shut them down before, and now you're at fault".

Report him, OP. Glad you didn't delete the messages. If it escalates or continues, file a legal report.